The present invention relates to a stereoscopic image display apparatus, particularly to be used preferably for stereoscopically displaying an image on a display device (display) e.g., TV, VCR, computer monitor, game machine and the like, and stereoscopically viewing the displayed image from a predetermined observation area.
As a conventional viewing method of a stereoscopic image, various methods have been suggested, for instance, a method of using polarizing glasses to show a viewer parallax images based upon mutually different polarizing states, or a method of using a lenticular lens to lead a predetermined parallax image of plural parallax images (viewpoint image) to a viewer's eye, and the like.
In the method of using a lenticular lens for stereoscopically displaying an image without wearing a special polarizing glasses, the lenticular lens is provided on the viewer's side of the display device so as to give directivity to each pixel of the parallax images displayed on the display device, thereby enabling the viewer to recognize a stereoscopic image.
The method of using the lenticular lens has an advantage of enabling stereoscopic viewing without using polarizing glasses. However, the method has a problem of glaring surface of the display because of the fact that a lenticular lens sheet is provided on the front surface of the display.
To cope with this problem, the inventor of the present invention has developed a stereoscopic image display apparatus disclosed in Japanese Patent Application No. 8-148611 enabling the viewing of a satisfactory stereoscopic image from a wide area.
The above application No. 8-148611 discloses a stereoscopic image display apparatus comprising: light source means for emitting light from plural apertures, having a light source and a mask substrate provided with a mask pattern having plural apertures; a micro-optical device having different optical effect in the horizontal and vertical directions; and a transmission-type display device. According to this stereoscopic image display apparatus, right stripe pixels and left stripe pixels, obtained by dividing each of a right-eye parallax image and a left-eye parallax image into multiple stripe patterns of pixels, are alternately arrayed in a predetermined order whereby forming one image as a stripe-combined image to be displayed on the display device; light emitted by the light source means is provided with a directivity by the micro-optical device so as to irradiate the stripe-combined image; and the light is separated into at least two areas, enabling the viewer to recognize the stripe-combined image as a stereoscopic image.
Note that the stereoscopic image display apparatus disclosed in Japanese Patent Application No. 8-148611 will be referred to as "the conventional stereoscopic image display apparatus" hereinafter.
In the conventional stereoscopic image display apparatus, the mask pattern is configured with apertures and light shielding portions arranged in a checked pattern. As a micro-optical device, two lenticular lenses each consisting of plural cylindrical lenses having refractive power in one direction are arranged such that the cylindrical lenses are arranged orthogonally.
Accordingly, an area from which an image on a display can be stereoscopically viewed is enlarged, making it possible to view an excellent stereoscopic image from a wide area.
Generally, in order to view an excellent stereoscopic image having high precision by the stereoscopic image display apparatus, it is important to have flexibility in precise adjustment during the assembly of each of the components constructing the entire apparatus.